In producing a yarn formed of staple fibres or predominantly of staple fibres, such as wool, cotton, synthetic staple fibres, or a mixture of such fibres, a number of slivers may, typically after drafting, be passed through a twisting stage which comprises reciprocating rotating rollers which move from side to side as the slivers pass between the rollers, thereby imparting a twist to the strands. After exiting the twist rollers, the strands are brought together to twist naturally with each other to form a multi-ply yarn. Apparatus or machines for so producing a yarn are disclosed in Australian patent specifications 51009/64, 9432/66, 26099/67, and 25258/71.
New Zealand patent 336048 discloses a method for producing a yarn comprising three or more slivers, or ends, in which the three slivers are passed between reciprocating twist rollers and then one or more of the slivers is passed over a path of a different length before the slivers are brought together. Rather than all of the slivers or ends passing through the twisting stage together and then being twisted naturally together, the twist in one or more of the slivers or ends is staggered or out of phase relative to the twist in the other slivers.